An ORIGINAL 5/16" SIZE COMBINATION SOCKET BIT for a North Brothers "Yankee" No. 31 or 131 reciprocating screwdriver by the North Brothers Division of Stanley Tools, Philadelphia, Pennsylvania. This bit, which was part of a series of such bits produced for the "Yankee" screwdriver line has a 5/16" diameter shaft to fit in the No. 31 and 131 screwdrivers. This "combination" pattern bit is designed for use with both hexagonal and square nuts. It will also work with the 31A and 131A screwdrivers. An uncommon "Yankee" tool in top collector quality condition. Length = 2.75 Inches (Ref. Id No.: 446914) [Free Shipping]